1. Field of the Invention
This invention relates, generally, to exercise devices. More particularly, it relates to a leg exerciser.
2. Description of the Prior Art
The art includes numerous leg exercising devices. U.S. Pat. No. 4,226,415 to Wright discloses a longitudinally extending table having a transversely disposed, movable cross bar mounted thereabove so that an exerciser may displace the cross bar by employing leg muscles, thereby strengthening said muscles. Resistance to movement of the cross bar is adjustable by means of valves connected to a hydraulic actuator. Such actuators are relatively expensive, however, and difficult to maintain in good operating condition.
Other exercise devices enable the exerciser to adjust the amount of resistance to muscle power through the use of weights; such devices are disclosed in U.S. Pat. Nos. 4,405,128 to Mclaughlin et. al. and 4,634,127 to Rockwell. In devices of this type, variable resistance is obtained by changing the amount of weights to which the movable parts of the machine are connected. Weights, of course, are heavy. They make devices that rely on them expensive to ship.
Still other devices employ springs; examples of such devices are found in U.S. Pat. Nos. 5,002,271 to Gonzales, 5,072,932 to Johnson, and German patent No. 23 35 022. None of these device include any means for adjusting the bias of the springs. Springs are inexpensive, light-in-weight, and easy to maintain.
What is needed, then, is an exercising device having a resistance supplied by springs or equivalents thereof which can be easily adjusted by the exerciser. In view of the prior art at the time the present invention was made, however, it was not obvious to those of ordinary skill in the art of machine design how the needed device could be supplied.